He's either Croatian or Serbian, NIKO BELLIC is not a Bosnian name, we Bosnians have Muslim based names, so Niko is prob. Croatian or Serbian, if he was Muhammad Belic then he'd be Bosnian.

He's defintively not Bosnian but since when he gets off the ship Roman says "Zdravo, buraceru" he's probably Serb 'cause I don't think that we say to someone in Croatia: Zdravo, burazeru. As in joke yes but to someone who's Croat you would go home with a fist trace in your face. Well I think we would.